package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{

    private String name;//锁的名称
    private StringRedisTemplate stringRedisTemplate;
    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT ;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(StringRedisTemplate stringRedisTemplate, String name) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }

    @Override
    public boolean tryLock(long timeoutSeconds) {
        //获取线程标识（id）
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁
        Boolean success= stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX+ name, threadId,timeoutSeconds, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }
    /*
    * lua脚本
    * */
    @Override
    public void unlock() {
        //调用脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX+ name),
                ID_PREFIX + Thread.currentThread().getId()
                );
    }


    /*@Override
    public void unlock() {
        //获取线程标识
        String threadId = ID_PREFIX + Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        //判断标识是否一致
        if(threadId.equals(id)){
            //释放锁
            stringRedisTemplate.delete(KEY_PREFIX+ name);
        }
    }*/
}
